Some of those living in France and working in Switzerland, declare their French home as a secondary residence and claim to reside primarily in Switzerland. This makes them Swiss taxpayers, depriving the French communes where they live of tax revenue, a sum estimated at around 40 million euros.

After a campaign of flyers the commune posted a video urging “false residents” to come clean.

The film explains the risks of not setting the records straight – criminal prosecution for tax evasion, and explains a sort of commune amnesty that will run until 30 June. Those who come clean will be treated as if they had just arrived to live in the commune. Antoine Vielliard, the mayor of Saint-Julien-en-Genevois, described the action as their version of Papyrus, Geneva’s amnesty on illegal immigrants.

The state of Geneva deducts tax at source from the salaries of French residents. Two thirds of this tax is retained by Geneva while the other third is paid to the French tax authorities. Only those declaring primary residence in France have their taxation treated in this way.

Antoine Vielliard told Tribune de Genève that they estimate there are around 20,000 “false residents” pretending to live Geneva across all of neighbouring France, which would add up to around 40 million euros of lost tax revenue. In Saint-Julien-en-Genevois he reckons there are around 600, estimated to cost the commune 2 million euros.

An internet page has been set up by the commune to guide people through the process of declaring French residency.

Something not mentioned in the film are the new rules the French government imposed on Swiss estates inherited by French residents. On 1 February 2015, France introduced rules to tax Swiss inheritance based on the residence of the recipient and not, as is typically the case, the residence of the deceased.

Residence irregularities will be easier to spot from 1 January 2018 when automatic international exchange of bank account information swings into operation.